This invention relates to fans for a computer system.
Most modern computer systems include fans that are used for cooling. Fans are particularly important in modern systems that employ processors operating at high clock speeds and/or compact computer housings.
Particularly as fans include moving components, they are vulnerable to failure in use. It is important, therefore, that fans can readily be replaced in the event of a failure. Typically, a faulty fan can be removed from a computer chassis by taking the cover off the computer system, disconnecting the electrical connections for the fan power supply and any sensors, releasing screws securing the fan in the computer chassis and lifting out the fan. A replacement fan can the be installed by the reverse series of operations, namely placing the fan in the appropriate location, fastening screws securing the fan in the computer chassis, making the electrical connections for the fan power supply and any sensors, and replacing the cover on the computer system. This process can be relatively time consuming, particularly if the screws securing the fan in place are not readily accessible. One would like to be able to minimise the downtime of the computer system when replacing a fan, particularly if the computer system concerned is a server providing services to clients.
The present invention seeks to address this by improving the ease of installation and/or removal of one or more fans in a computer system.
A first aspect of the invention provides a fan carrier for a computer system. The fan carrier defines an enclosure for receiving at least one fan unit. The fan carrier includes a first wall that includes at least one air vent and a second wall substantially perpendicular to the first wall. The first and second walls form two walls of the enclosure. Extensions from the second wall extend outwardly from the enclosure to define ears with locating lugs for locating the fan unit in a housing of the computer system.
An embodiment of the invention enables a fan subassembly that includes the fan carrier and at least one fan secured therein, whereby the fan assembly can be installed in the computer system much more easily that a fan without the carrier. The fan subassembly can be located adjacent a vented portion of a housing wall of the computer system in a gap in a flange of that housing wall. Each ear of the fan carrier is configured to overlie a portion of that flange adjacent the gap with the lug being received in a hole in said portion of the flange. The fan subassembly can then be clamped in place by securing the cover to the housing, the cover clamping the ears over the flange with the lugs in the receiving holes in the flange. This arrangement allows for the fans to be mounted in the computer housing without any tools other than those that may be needed to secure the cover of the housing. This can greatly increase the speed of replacement of a faulty fan unit, as well as facilitating initial assembly of the computer system.
The fan subassembly can be pre-assembled, with the fan or fans being secured in respective enclosures formed within the fan carrier using appropriate fastenings, for example screws that pass through holes in the first surface of the fan carrier.
A wire mesh can be provided to cover the aperture or apertures that form the vent in the first wall of the fan carrier. The wire mesh can prevent fire escaping from the housing in the event of a catastrophic failure of the computer system that causes a fire. The fire mesh can advantageously be secured in place between the first wall and a fan unit in the enclosure by the fasteners that secure the fan unit in the enclosure.
A third wall of the fan carrier substantially perpendicular to the first and second walls can further define the enclosure for a fan unit. Yet a further wall substantially parallel to the third wall which further wall extends away from the first wall by a distance greater than a depth of the enclosure, can be used to define a handle for manipulating the fan carrier.
A particular example of a fan carrier according to the invention defines first and second enclosures, each for receiving a respective fan unit. This fan carrier comprises third and fourth walls substantially perpendicular to the first and second walls and substantially parallel to each other, the third wall and fourth walls each form a wall of a respective fan enclosure. In this example, a further wall is provided that is substantially parallel to and is intermediate the third and fourth walls. This further wall separates the two enclosures and extends away from the first wall by a distance greater than a depth of each enclosure to define a handle for manipulating the fan carrier. This further wall can also serve to separate the airflow for the two fans in the adjacent enclosures.
The first wall of the fan carrier can be provided with a protrusion (e.g. a lip adjacent one edge thereof) to space the first wall from an abutting surface.
The fan carrier can be formed from sheet metal, for example from zinc plated mild steel. Electromagnetic interference (EMI) fingers can be secured to the second wall to reduce or prevent EMI from escaping from the computer housing.
Another aspect of the invention provides a fan subassembly comprising a fan carrier as described above in combination with at least one fan secured therein. Each fan unit can be provided with electrical connections for electrically connecting the fan units to the computer system.
A further aspect of the invention provides a computer system comprising a housing and a fan subassembly as described above. The fan subassembly can be located adjacent a vented portion of the housing wall of the computer system in a gap in a flange that extends along at least part of the housing wall. An ear of the fan carrier overlies a portion of the flange adjacent the gap and a lug on the ear is received in a hole in the flange. The cover, when in place on the computer housing, overlies the first wall of the fan carrier and the ears to secure the fan subassembly in place by bearing the ears down on the flange.
A method of installing a fan in a computer system includes providing a fan subassembly as described above. The fan subassembly is placed adjacent a vented portion of a wall of a housing of the computer system in a gap in a flange at an edge of the housing wall with ears of the fan carrier overlying a portion of the flange either side of the gap and with lug on the ears being received in respective holes in the flange. Electrical connections for the fan power supply and any sensors are made. Then the cover is placed on the computer system such that the cover overlies the first wall of the fan carrier and the ears to secure the fan subassembly in place by bearing the ears down on the flange.
A method of replacing a fan subassembly includes removing a cover of the computer system. Electrical connections for the fan power supply and any sensors are disconnected. Then the fan subassembly is lifted out and a replacement fan assembly is installed as described above.
It will be appreciated that the installation and replacement of the fan assembly can be achieved without the use of any tools other than any needed for removing and/or attaching the cover of the computer system.
Further aspects and advantages of the invention will become apparent from the following description of a preferred embodiment.